GB922687A - Machine tool control mechanism - Google Patents

Abstract

922,687. Machine tool details. S. R. CUDNOHUFSKY. Sept. 1, 1961 [June 21, 1961], No. 31494/61. Class 83 (3). The rotating or reciprocating table 12 of a machine tool is moved relative to the base 10, by a rotary or reciprocating motor 14, which is stopped at predetermined positions when the back pressure is built up in hydraulic conduits 70,120,104, by a valve 22, having a stylus 20 actuated by a template 16 carried by table 12. Valve 22 is movable perpendicular to the direction of travel of table 12, by a hand wheel 26, or a piston (not shown), and comprises a piston 32 slidable in a bore 30, and a shoulder 42 on the piston, which co-operates with a shoulder 74 in the bore, to form a restriction 76 for fluid passing through a conduit 40. The fluid passes from the restriction 76, through radial passages 48, and a bore 50, and is then discharged through a port 38. A plunger 52, guided by a bearing 68, engages the end of piston 32, and also a lever 60 which pivots at 62, and carries stylus 20, the limit of such pivoting being controlled by a screw 66. Fluid for operating motor 14 is supplied by a lowpressure pump 80, through a conduit 82, a pilot valve 86, a directional valve 88, and a conduit 102, and is discharged from the motor through conduit 104, valve 88 and conduit 120, until it joins hydraulic fluid supplied to a conduit 70 by a high-pressure pump 106, which controls valve 22. In operation with a tool mounted on base 10, and a workpiece mounted on table 12 (or vice versa), a switch is depressed to energize a solenoid 90, and valve 86 moves to the position of Fig. 2. Oil flows from pump 80 through conduit 82, and conduit 96, to actuate a cylinder 94 to position valve 88, thus allowing oil to flow to motor 14 through conduit 102. Oil exhausts from motor 14, through conduit 104, and merges with oil flowing from pump 106, and thence through restriction 76 in valve 22, and to a sump 112. The table is moved in the direction of the arrow, Fig. 2, by motor 14, until shoulder 18 on template 16 engages stylus 20, whereupon lever 60 is pivoted in a counterclockwise direction, thus closing restriction 76. Pressure is built up in lines 70, 104 and 120, until it equals the driving force on motor 14, thus stopping the latter and therefore table 12, and a machining operation is carried out. Valve 22 is retracted to allow stylus 20 to clear shoulder 18, by hand wheel 26, and piston 32 in valve 22, is moved downwardly to relieve restriction 76. Motor 14 is again driven until stylus 20 engages shoulder 18a, and a second machining operation is carried out. The direction of motor 14 is reversed by actuating a solenoid 92 to move valves 86, 88, to reverse the lines 102, 104, to motor 14, and rapid table return is provided by an unloading valve 114.